Heating, Air Conditioning, Fridge, HVAC/Strange A/C Behavior

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Question
Hello,

I'm hopeful you can help me or at least provide ideas.  My question is a little different.. as it pertains to a portable stand-up air conditioner (Brand: Everstar, 10K BTU).

The unit has a built-in thermostat and a "Cool" mode, with the ability to keep the fan running when it isn't cooling -- this is the mode I leave it on.

When the compressor is about to kick, the fan accelerates a bit first.. for perhaps 10 seconds, then the compressor starts.  This is the normal behavior.

At times, the fan accelerates as normal... goes for about 30 seconds (not 10) at this high speed and decelerates, with the compressor never kicking on.  It will then try again in another 45-60 seconds... eventually starting up after 5-10 cycles of doing this.

From a DIY perspective, can you provide any ideas why this might be?  Failing compressor?  Lack of airflow?  Overly sensitive/failing thermostat?   Just looking for ideas in order to troubleshoot.

This seems to be intermittent and tends to happen when it is relatively 'cool' aka, barely warm enough for the unit to 'want' to cool.  Due to this and the lack of bad sounds, I am leaning toward the thermostat being too sensitive and/or failing.  What happens when a thermostat begins to fail, do you know?

Thanks a bunch.

Answer
Manny,

Your compressor start relay may be weak and preventing the compressor from starting smoothly , possibly a weak run capacitor for the compressor. Possibly you have some burnt wires going to the compressor,or the wires at the compressor hookup are corroded or burnt. You can physically bypass the thermostat and use the wall plug to start it ,see if you have the same issues, if so your thermostat is not the problem.

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40+ years diversified experience.An HVAC/Refrigeration Self Employed Contractor since 1986. NATE Certifield. Answer questions pertaining to Residential and Commercial Air Conditioning , Warm Air Heating, Heat Pump systems.Mechanical and Electrical troubleshooting of these systems.Be as detailed as possible when describing problem.Packaged unit or split systems.No appliance questions.

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Installation and Troubleshooting, Mechanical and Electrical, in following areas, Refrigeration ( Walk In and Reach In Coolers and Freezers ) Commercial Roof Top and Packaged Heating/Cooling ( Natural Gas,Propane, Electric, and Heat Pumps ) Computer Room Air Conditoning Systems,Commercial Residential Packaged and Split Systems Air Conditoning and Heat Pumps.Warm Air Oil , Natural and Propane Gas Heating systems.

Education/Credentials
Graduated from Private Technical School in 1975. An HVAC/Refrigeration Contractor . Have Unlimited Heating/Piping and Cooling Contractor License.Limited Sheetmetal Contractors License.NATE Certifield. York Certifield Master Heat Pump Technician 1986. Served 33 years combination Active Duty Air Force , Air Force Reserves and Air National Guard in the HVAC/Refrigeration Shop/Mechanical Shop. Troubleshooting/Installing HVAC/Refrigeration Equiptment Worldwide. Retiring in 2003 as a Senior NCO ,and a Mechanical Superintendent.

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